1. Field of Invention
The present invention relates to a liquid crystal display, more particularly, relates to the pixel circuit in the liquid crystal display.
2. Description of Related Art
A liquid crystal display (LCD) comprises the scan switches, liquid crystal capacitors, and storage capacitors, wherein the storage capacitors can store the analog gray scale potential. Generally, common electrode voltage (VCOM) may use the direct current (DC) potential or the alternating current (AC) potential to drive the liquid crystal display. Both the DC potential and the AC potential may reverse the liquid crystal potential, thus prolonging the service life of the liquid crystal.
When the liquid crystal potential is reverted, pixel units and data lines may undergo twofold gray scale potential charging. However, in order to lower the overall cost, the conventional driving circuits wouldn't be provided with oversized driving buffers. Therefore, when the liquid crystal potential reversion is performed under greater gray scale potential, the liquid crystal display usually employs a pre-charge design to reduce the amount of buffers, so as to meet the consideration of the cost.
Common potential pre-charge design couples the data lines to the fixed potential, and uses this fixed potential to charge the data lines, so as to accomplish the purpose of pre-charging the potential. However, such design may pre-charge the potential of the data lines, from the perspective of overall power consumption, just replaces the power consumption of the buffer with the power consumption of the potential source. Although it may reduce the cost and difficulty in the buffer designing, it nevertheless doesn't reduce the power consumption of the liquid crystal display.
Hence, there is requirement in the related art to provide a pre-charge design to substantially reduce the overall power consumption of the liquid crystal display.